This invention relates to thermal and noise insulation of the axial end walls of heated or cooled temperature controlled rotary cylinders, as for example the type of rotatable cylinders used in the paper manufacturing industry, and more particularly to the insulator blanket and the mounting of the insulator blanket to the cylinder end wall.
In the process of manufacturing paper products, wet paper is moved in a web about a plurality of heated rotary cylinders, and the heated cylinders progressively dry the paper. The rotary dryer cylinders can be heated from various heat sources, with a common heat source being superheated steam at a temperature sufficient to heat the cylindrical convex surface of the dryer cylinder to the desired temperature, usually between 100.degree. F. and 600.degree. F. The steam is transmitted under pressure through the axles of the dryer cylinders to heat the inside of the dryer cylinders.
Since the web of paper makes continuing contact with the external convex surface of the dryer cylinder wall during the operation of the dryer cylinder, a major portion of the heat applied to the cylindrical wall of each dryer cylinder is absorbed by and taken away by the paper; however, the web of paper does not contact the axial end walls of the dryer cylinders and most of the heat from inside each dryer cylinder that is transferred through its axial end walls is lost to the atmosphere.
Some attempts have been made to insulate the axial end walls of heated dryer cylinders. For example, the prior art discloses clamping a pair of semi-circular solid insulator panels to the connector screws of the axial end walls of a dryer cylinder. Supporting a solid insulator panel in two halves at the end of a rotatable dryer cylinder is believed to be somewhat hazardous since the halves may tend to part under the stress of centrifugal force and fly off of the rotary cylinder.
While the placement of an insulator panel adjacent the axial end wall of a rotary cylinder tends to reduce the rate of radiant heat transfer from the axial end wall, it is also desirable to retard the transfer of heat due to convection heat transfer. During the rotation of a rotary dryer cylinder, the rotation of the cylinder tends to induce a flow of air radially outwardly of the rotating axial end walls, and the constant flow of air across the axial end wall results in a substantial heat loss from the axial end wall of the rotary cylinder. Also, the turbulent air currents normally present in a paper mill tend to increase convection heat transfer at the axial end walls of a rotating dryer cylinder.